Start by lining a 9x9 inch baking dish with parchment paper, allowing some overhang for easy removal later.
In a medium saucepan over medium heat, melt the unsalted butter. Stir occasionally to make sure it doesn’t burn.
Once the butter is fully melted, add the granulated sugar and milk. Stir until it comes to a gentle boil, then boil for about 1 minute, stirring continuously.
Remove the saucepan from heat. Immediately add the semi-sweet chocolate chips and stir until completely melted and smooth.
In a large mixing bowl, combine the quick oats, chopped pecans, graham cracker crumbs, and vanilla extract. Pour the melted chocolate mixture over the dry ingredients and mix until well combined.
Spoon the mixture into the prepared baking dish. Use a spatula or your hands to press the mixture down firmly and evenly.
Refrigerate the bars for at least 2 hours, or until firm, to help them set properly.
Once set, lift the bars out using the parchment paper overhang. Cut into squares or rectangles and serve.
